It is often desirable to attach elements to beams, such as the horizontal beams on boats such as pontoon boats, railings, fences, chair backs, chair arms. For example, it may be desirable to attach a cup holder, hooks, flag holder, pennant holders, or other holding elements to such beams. It is further desirable to attach such elements can be easily attached and removed as desired, without the use of tools and without damaging the beam, and that the attachment be secure, such that it does become disengaged when bumped or when jostled, such as by motion of the thing to which it is attached.